Metallic vs Ceramic Bracket Failures After 12 Months of Treatment: A Prospective Clinical Trial

INTRODUCTION

Orthodontic treatment with fixed vestibular appliances is still widely used worldwide. When choosing the aesthetic alternative of ceramic brackets, the possibility of failure and cracking of braces should be considered. Therefore, the aim of the present study was to compare the failure rates of ceramic and metal brackets in a 12-month clinical study.

METHODS

Eighty patients undergoing fixed orthodontic treatment with vestibular appliances were enrolled and divided into 2 equal groups: MET for metal brackets and CER for ceramic brackets. After bonding, bracket failures were recorded for 12 months, along with the archwire placed at the time of failure. Angle's dental class, skeletal class, Wits appraisal, Little's irregularity index, overjet, overbite, age, and gender of the patients were recorded from pretreatment cephalometric tracings and study casts. The data were statistically analysed (P < .05).

RESULTS

Significantly higher failure rates were found for ceramic brackets in the overall analysis, in the mandibular arch, and in the posterior region. Regression analysis revealed a significant influence of round nickel-titanium archwires on higher failure rates, whilst a significant influence of rectangular archwires was found on lower failure rates.

CONCLUSIONS

Ceramic brackets showed higher failure rates. Patients should be aware that orthodontic treatment with ceramic brackets may involve delays and inconvenience due to the higher failure rate compared to metal brackets.

A review and evaluation of orthodontic brackets, molar bands and orthodontic auxiliaries during orthognathic surgery: A prospective cohort study

OBJECTIVE

The primary aim of this study was to provide a review of the types and frequency of orthodontic brackets, molar bands and orthodontic auxiliaries used for patients undergoing orthognathic surgery. The secondary aim was to evaluate the risk of failure of these items during orthognathic surgery.

METHODS

From three Dutch hospitals, 124 adult patients were included in this prospective cohort study. Five independent researchers collected the data during surgery using a specifically created data extraction form. The type of surgery, surgeon, orthodontist and type of orthodontic bracket, molar band or auxiliary were noted for each tooth. To evaluate their failure risk, the following variables were noted: failure and site; and type and cause of failure.

RESULTS

Stainless-steel brackets were the most frequently (75.8%) used bracket type seen in patients undergoing orthognathic surgery. Ceramic brackets were seen in 24.2% of the cases and were only applied in the anterior region. Molar bands were present in 58.9% of the patients and mostly with bands on the first molars in combination with bonded tubes on the second molars. In 32.2% of all cases, one or more failures were noted. One-third of all failures were described as detachment of the molar tube on the most posterior molar. Kobayashi ligatures and powerpins showed the highest risk of failure (odds ratio [OR] 3.70, 95% confidence interval [CI] = 1.91-7.15). No significant difference in failure rate was found between stainless-steel brackets, molar bands (OR 0.34, 95% CI = 0.08-1.43) and ceramic brackets (OR 0.44, 95% CI = 0.14-1.45).

CONCLUSION

Stainless-steel brackets, ceramic brackets, molar bands and surgical hooks are suitable for orthognathic cases. Kobayashi ligatures and powerpins had a significantly higher risk of failure so are not recommended for temporary intraoperative maxillomandibular fixation (TIO-MMF).

The Use of Laser Energy for Etching Enamel Surfaces in Dentistry-A Scoping Review

BACKGROUND

In dental practice, different situations require etching the enamel layer. Acid etching, the present golden standard, may be replaced by other methods, such as laser etching. The main focus of our scoping review is to assess the existent literature regarding the effectiveness of different types of lasers, to identify the main aspects studied so far, and to understand where new search strategies are needed.

METHODS

The search was conducted in several databases focusing on the laser etching of human definitive enamel. We included English language articles published between January 2000 and December 2021.

RESULTS

The 34 articles reviewed showed that hard lasers, Er:YAG, Er,Cr:YAG, may represent an alternative etching method on enamel surfaces. They create a fractured, irregular surface and open dentin tubules, highly suitable for adhesion but with a lower risk of cavity formation. Nd:YAG, CO₂, and Diode lasers do not help in creating sufficient shear bond strength. There is, however, evidence suggesting that microcracks in the enamel layer may appear after thermomechanical ablation using laser energy.

CONCLUSIONS

While the use of acid etching is still successfully used for enamel conditioning, some researchers have emphasized the role played by saliva in the enamel-remineralization process a few days after the procedure. In this context, laser energy can be used, especially for bonding ceramic brackets in the case of orthodontic treatments. However, as thermomechanical ablation can generate microcracks, further research is required in order to establish clear findings concerning the use of laser energy on enamel etching.

Safe Debonding of Fixed Appliances: A Comparison of Traditional Techniques and LODI Devices on Different Bracket Types in Terms of Enamel Cracks, Site of Bond Failure, and Bracket Reusability

The objective of this study was to compare the effects of the debonding of three different bracket types by means of three popular debonding methods. A total of 180 human third molars was divided into six groups, consisting of 20 teeth each. Three bracket types were bonded to the enamel (metal brackets with an integral base and a foil mesh base, and ceramic brackets) and three methods of bracket debonding were employed (bracket removal pliers, Weingart pliers, and Lift-Off Debonding Instrument). The samples were examined with scanning electron microscopy to assess the number of enamel cracks, measure the area of adhesive remaining on the enamel, and calculate the adhesive remnant index (ARI). There were no statistically significant differences between the groups in terms of the number of enamel cracks after bracket debonding. The amount of adhesive remaining on the teeth after the brackets were removed was significantly different between the groups. LODI and Weingart pliers are considered to be the safest methods of debonding brackets with an integral base, while LODI is the best tool for brackets with foil mesh. Bracket removal pliers are considered to be the preferred method for ceramic bracket debonding.

Bond Strength of Metallic or Ceramic Orthodontic Brackets to Enamel, Acrylic, or Porcelain Surfaces

Bonding strategies within different brackets and dental materials are still a challenge concerning adhesion and dental surface damage. This study compared the shear and tensile bond strength of orthodontic ceramic and metallic brackets to enamel, acrylic, and ceramic surfaces after thermal cycling. Dental surfaces were divided into three groups: enamel, ceramic, and acrylic. Each group received stainless-steel and ceramic brackets. After thermal cycling, specimens were randomly divided into two subgroups considering tensile (TBS) or shear bond strength (SBS) test. After the mechanical testing, scanning electron and optical microscopy were performed, and the adhesive remnant index (ARI) was determined. The two-way ANOVA full factorial design was used to compare TBS, SBS, and ARI on the surface and bracket type (α = 0.05). There were significant differences in TBS, SBS, and ARI values per surface (p < 0.001 and p = 0.009) and type of bracket (p = 0.025 and p = 0.001). The highest mean SBS values were recorded for a ceramic bracket bonded to an acrylic surface (8.4 ± 2.3 MPa). For TBS, a ceramic bracket bonded to acrylic showed the worst performance (5.2 ± 1.8 MPa) and the highest values were found on a metallic bracket bonded to enamel. The adhesion of metallic or ceramic brackets is enough for clinical practice although the damage of the enamel surface after debonding is irreversible and harmful for the aesthetic outcome of the teeth.

Effects of one-step orthodontic adhesive on microleakage and bracket bond strength: An in vitro comparative study

OBJECTIVE

To evaluate the effects of one-step orthodontic composite combined with primer on microleakage and shear bond strength (SBS) of metal and ceramic brackets.

MATERIALS AND METHODS

This in vitro study included 144 extracted premolar teeth. Teeth were divided into two main groups according to the bracket type (metal and ceramic). In each group, brackets were bonded with three different bonding systems: two-step total-etch (37% phosphoric acid+Transbond XT primer+Transbond XT light cure adhesive), one-step self-etch (Transbond Plus self-etch primer+Transbond XT light cure adhesive), and one-step orthodontic adhesive (37% phosphoric acid+GC Ortho Connect light cure adhesive). A total of 6 groups (n=12) were performed for each evaluation. All samples were subjected to thermal cycling. After dye penetration, sections were prepared and assessed under stereomicroscope. After SBS test, adhesive remnant index (ARI) scores were determined. Data were analyzed statistically.

RESULTS

There were no significant differences between total-etch and one-step orthodontic adhesive for microleakage. Self-etch adhesive showed more microleakage at occlusal interfaces (P<0.05). The highest and lowest mean SBS values were found in ceramic brackets bonded with total- and self-etch adhesives, respectively. No significant differences were found among the SBS values of the groups. However, the differences between ARI scores were found statistically significant (P<0.05).

CONCLUSIONS

Orthodontic composite integrated with primer can be used safely instead of two-step total-etch adhesives during the bonding of metal and ceramic brackets due to less microleakage and adequate SBS values.

Influence of phototherapy on bond strength and failure modes of enamel bonded to ceramic and metallic brackets with different surface treatment regimes

AIM

The aim of the current study was to assess efficacy of phototherapy on mode of failure and shear bond strength among different brackets in combination with dissimilar conditioning regimens on enamel surface.

MATERIAL AND METHODS

Ninety maxillary premolars were arbitrarily assigned into six groups (n = 15 each) based on surface conditioning of enamel. Group 1 and group 2 surface treated with total etch + rinse. Group 3 and group 4 surface conditioned with Er,Cr:YSGG. Group 5 and group 6 surface treated with self-etching primer (SEP). Now based on the type of bracket bonded to enamel surface. Group 1, 3 and 5 were bonded to metallic brackets (MB). Similarly, group 2,4,6 were bonded to ceramic bracket (CB). All samples from each group were positioned in a in a universal testing machine for shear bond strength testing. Ten samples from each group were used to discover the sites of bond failure using ARI with stereomicroscope. The mean shear bond strength of six groups were compared by analysis of variance (ANOVA) and pairwise comparison between groups were analysed with the Post hoc Tukey test at a significance level of (p < 0.05).

RESULTS

The maximum SBS values were displayed by group 1 total etch + rinse MB (14.84 ± 1.78) whereas the minimum shear bond strength values were exhibited by group 6 SEP CB (9.99 ± 0.91). Samples treated with total etch + rinse MB (14.84 ± 1.78) and group 3 Er,Cr:YSGG MB unveiled comparable bond strength (p > 0.05). Similarly, experimental group 2 total etch + rinse CB (12.52 ± 1.28) was found to be comparable to group 4 Er,Cr:YSGG CB (12.14 ± 4.12) (p > 0.05).

CONCLUSION

Enamel etched for bonding bracket with Er,Cr:YSGG phototherapy at (4.5 W and 30 Hz) displayed comparable bond strength to conventional Transbond XT independent on the type of brackets used.

Shear bond strength of ceramic and metallic orthodontic brackets bonded with self-etching primer and conventional bonding adhesives

Introduction

Adult patients typically require high-quality orthodontic treatment for ceramic brackets, but some clinicians remain concerned about the bond strength of these brackets. Therefore, the aim of this study was to determine the shear bond strength and de-bonding characteristics of metallic and ceramic brackets bonded with two types of bonding agents.

Methods

In an experimental study done in 2013 in Babol, Iran, 120 extracted human maxillary premolar teeth were randomly divided into four groups as follows: HM group: metallic bracket/conventional bonding agent; SM group: metallic bracket/Transbond self-etching primer; HC group: ceramic bracket/conventional bonding agent; SC group: ceramic bracket/Transbond self-etching primer. Twenty-four hours after thermocycling (1000 cycle, 5 °C–55 °C), the shear bond strength values were measured. The amount of resin remaining on the tooth surface (adhesive remnant index: ARI) was determined under a stereomicroscope. Enamel detachment index was evaluated under a scanning electron microscope. To perform statistical analysis, ANOVA, Kruskal–Wallis, and Tukey post-hoc tests were applied. The level of significance was set at p <0.05.

Results

The mean shear bond strength values (MPa ± SD) were group HM=12.59, group SM=11.15, group HC=7.7, and group SC=7.41. Bond strength differences between groups HM and SM (p=0.063) and between HC and SC (p=0.091) were not statistically significant. There were significant differences between HM and HC and between SM and SC groups (p < 0.05). Insignificant differences were found in ARI among all groups.

Conclusion

Our findings indicated that the metallic brackets had higher bond strengths in comparison with ceramic brackets. In addition, self-etching primer was able to produce fewer bonds compared with the conventional technique. Many samples showed the bracket-adhesive interface failure or failure inside the adhesive.

Comparison of shear bond strength and bonding time of a novel flash-free bonding system

OBJECTIVE

To evaluate the bonding time, shear bond strength (SBS), and adhesive residue index (ARI) of APC(TM) Flash-Free bonding system.

MATERIALS AND METHODS

Thirty-six extracted human maxillary premolars were randomly divided into three groups (12 per group) and used for this in vitro study: group 1, APC Flash-Free Adhesive Coated Appliance System; group 2, Clarity ADVANCED Ceramic Bracket pasted manually; group 3 (control group), 3M APC PLUS Adhesive prepasted brackets bonded with the extruded flash removed. Bonding time was measured using a stopwatch. Bond strength was measured using an Instron at a cross-head speed of 1 mm/min. The ARI was graded on a scale from 1 to 5. Repeated-measures analysis of variance and post hoc Tukey tests were used for statistical analysis.

RESULTS

It took significantly (P < .001) less time to bond in the APC Flash-Free Adhesive group (30.7 ± 3.3 seconds) compared with the control group (41.8 ± 4.0 seconds) and the manual group (39.2 ± 2.8 seconds). The APC Flash-Free Adhesive coated bracket had significantly (P < .001) greater SBS (13.7 ± 2.2 MPa) compared with the control group (10.8 ± 2.0 MPa) and the manual group (10.4 ± 1.4 MPa). The ARI was significantly (P < .001) greater with the APC Flash-Free Adhesive coated bracket compared with that of the other two groups.

CONCLUSIONS

Compared with other methods of bonding, the APC Flash-Free Adhesive Coated System can potentially reduce bonding time while increasing SBS.

The effect of vertical bracket positioning on torque and the resultant stress in the periodontal ligament--a finite element study

Background

The ideal built-in tip and torque values of the straight wire appliance reduce the need for wire bending and hence reduce chair time. The vertical position of the bracket on the tooth surface can alter the torque exerted on the tooth. This is a result of the altered surface curvature observed at each vertical position. To further clarify the role of vertical bracket positioning on the applied torque and the resultant stresses in the periodontal ligament (PDL), we designed a mandibular first premolar using finite element modeling.

Methods

Cone beam computed tomography of 52 patients (83 lower first premolars) was selected to be included in the study. Curvature was measured for points along the labial surface with increasing distances (0.5 mm increments) from the cusp tip by calculating the angle between tangents drawn from these points and the axis joining the cusp tip and the root apex. The mean values for each distance were calculated, and a finite element model was designed incorporating these mean values. The resultant stress and hydrostatic pressure in the PDL were calculated using finite element analysis.

Results

The labial surface of the mandibular first premolar demonstrated a 26.39° change from 2.5 to 6 mm from the cusp tip. The maximum Von-Mises stress and hydrostatic pressure in the PDL were observed at the root apex for all of the bracket positions, and these values demonstrated, respectively, a change of up to 0.059 and 0.186 MPa between two successive points.

Conclusions

It can be concluded that the variation in the vertical position of the bracket can have an important effect on the torque and subsequently on the stresses and pressures in the PDL.

Effect of a DPSS laser on the shear bond strength of ceramic brackets with different base designs

This study evaluated the shear bond strength (SBS) and adhesive remnant index (ARI) of ceramic brackets with different base designs using a 473-nm diode-pumped solid-state (DPSS) laser to test its usefulness as a light source. A total of 180 caries-free human premolars were divided into four groups according to the base designs: microcrystalline, crystalline particle (CP), dovetail, and mesh. For each base design, teeth were divided into three different subgroups for light curing using three different light-curing units (LCUs) (quartz-tungsten-halogen unit, light-emitting diode unit, and a DPSS laser of 473 nm). Applied light intensities for the DPSS laser and the other LCUs were approximately 630 and 900 mW/cm(2), respectively. Stainless steel brackets with a mesh design served as controls. The failure modes of debonded brackets were scored using ARI. As a result, brackets bonded using the DPSS laser had the highest SBS values (16.5-27.3 MPa) among the LCUs regardless of base design. Regarding base designs, the CP groups showed the highest SBS values (22.9-27.3 MPa) regardless of LCU. Furthermore, stainless steel brackets with a mesh design had the lowest SBS values regardless of LCU. In many cases, brackets bonded using the DPSS laser had higher ARI scores and had more adhesive on their bases than on tooth surfaces. The study shows that the 473-nm DPSS laser has considerable potential for bonding ceramic brackets at lower light intensities than the other light-curing units examined.

Rebonding performance of different ceramic brackets conditioned with a new silane coupling agent

The objective of this study was to investigate the rebonding effect of a new silane coupling agent on various ceramic brackets bonded to ceramic specimen. Different ceramic brackets (Fascination 2, Clarity SL, and In-OvationC) were assigned to three groups: rebonding with new silane coupling agent, rebonding with conventional silane coupling agent, or regular bonding as control (n = 16). Bracket adhesion was calculated with a shear test in a universal testing machine. The bracket-composite-ceramic interface was evaluated using the adhesive remnant index score. One-way analysis of variance was applied for inferential statistics. Rebonding with the new silane coupling agent resulted in high shear bond strengths (SBSs; mean values: 37.44-41.24 MPa) and ceramic specimen fractures. Rebonding with the conventional silane coupling agent resulted in significantly (P < 0.001) lower clinically adequate SBS (mean values: 20.20-29.92 MPa) with the least ceramic specimen fractures. Regularly bonded ceramic brackets resulted in clinically adequate to high SBS (mean values: 17.06-41.56 MPa) depending on their bracket base design. Rebonded ceramic brackets showed sufficient SBS to ceramic specimen surfaces. However, increased bracket adhesion was associated with a risk of ceramic specimen surface damage. Therefore, ceramic brackets rebonded with the new silane coupling should be debonded cautiously using alternative debonding methods.

A comparative study of shear bond strength between metal and ceramic brackets and artificially aged composite restorations using different surface treatments

This in vitro study evaluated the shear bond strength (SBS) between ceramic brackets (CBs) and resin composite restorations (RCRs) prepared using different surface treatments. The findings were also compared with a similar study that used stainless steel brackets (SSBs). Forty-five premolars were restored with a nano-hybrid composite resin (Tetric EvoCeram) and randomly assigned to three surface treatment groups: group 1, 5 per cent hydrofluoric acid (HF); group 2, air abrasion (50 μm alumina particles); and group 3, diamond bur. Specimens were bonded with CBs (Fascination) and exposed to thermo-cycling (500 cycles). The shear force at a crosshead speed of 1 mm/minute was transmitted to brackets. The adhesive remnant index (ARIs) scores were recorded after bracket failure. The analysis of SBS variance (P < 0.01) and chi-square test of ARIs scores (P < 0.01) revealed significant differences among three groups tested. The SBS in group 3 (mean: 26.34 ± 4.76 MPa) and group 2 (mean: 26.68 ± 5.93 MPa) was significantly higher than group 1 (mean: 16.25 ± 5.42 MPa). The SBS was significantly higher in CBs (mean: 23.09 ± 7.19 MPa) compared to SSBs (mean: 15.56 ± 5.13 MPa). High ARIs (100 per cent) occurred in SSBs treated with a diamond bur, whereas CBs primarily failed at the resin-adhesive interface (P < 0.01). In two-thirds of the specimens (SSBs or CBs), no adhesive was left on the restoration after HF conditioning. The ARIs profile of CBs and SSBs that received surface treatments with air abrasion were similar (P > 0.05) and bond failure occurred mainly in adhesive-bracket base and resin-adhesive interfaces. The diamond bur surface treatment is recommended as a safe and cost-effective method of bonding CBs to RCRs.

Bonding with self-etching primers--pumice or pre-etch? An in vitro study

The purpose of this study was to compare the shear bond strengths (SBSs) of orthodontic brackets bonded with self-etching primer (SEP) using different enamel surface preparations. A two-by-two factorial study design was used. Sixty human premolars were harvested, cleaned, and randomly assigned to four groups (n = 15 per group). Teeth were bathed in saliva for 48 hours to form a pellicle. Treatments were assigned as follows: group 1 was pumiced for 10 seconds and pre-etched for 5 seconds with 37 per cent phosphoric acid before bonding with SEP (Transbond Plus). Group 2 was pumiced for 10 seconds before bonding. Group 3 was pre-etched for 5 seconds before bonding. Group 4 had no mechanical or chemical preparation before bonding. All teeth were stored in distilled water for 24 hours at 37°C before debonding. The SBS values and adhesive remnant index (ARI) score were recorded. The SBS values (± 1 SD) for groups 1-4 were 22.9 ± 6.6, 16.1 ± 7.3, 36.2 ± 8.2, and 13.1 ± 10.1 MPa, respectively. Two-way analysis of variance and subsequent contrasts showed statistically significant differences among treatment groups. ARI scores indicated the majority of adhesive remained on the bracket for all four groups. Pre-etching the bonding surface for 5 seconds with 37 per cent phosphoric acid, instead of pumicing, when using SEPs to bond orthodontic brackets, resulted in greater SBSs.